alternating-current motor

electrical engineering

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June 18, 2026

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An alternating-current (AC) motor is an electric motor that runs on AC power. A key type is the synchronous motor, which operates at a constant speed directly proportional to the power source's frequency. These motors use a stator with windings and a rotor that produces a constant magnetic field, often from permanent magnets or direct current. They are efficient and can control power factor, making them suitable for industrial processes and applications requiring precise speed, like clocks and timers.1

Another type is the AC commutator motor, often called a universal motor. It can run on either AC or DC power. These motors are commonly found in small appliances such as mixers, portable tools, and vacuum cleaners.2

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locomotive
Types of traction systems
The potential advantages of using alternating instead of direct current prompted early experiments and applications of this system. With alternating current, especially with relatively high overhead-wire voltages (10,000 volts or above), fewer substations are required, and the lighter overhead current supply wire that can be used correspondingly reduces the weight…
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The potential advantages of using alternating instead of direct current prompted early experiments and applications of this system. With alternating current, especially with relatively high overhead-wire voltages (10,000 volts or above), fewer substations are required, and the lighter overhead current supply wire that can be used correspondingly reduces the weight…
Read More

Galileo Ferraris
…right angles and powered by alternating currents that were 90° out of phase, thus producing a revolving magnetic field. The direction of the motor could be reversed by reversing the polarity of one of the currents. The principle made possible the development of the asynchronous, self-starting induction motor that is…
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…right angles and powered by alternating currents that were 90° out of phase, thus producing a revolving magnetic field. The direction of the motor could be reversed by reversing the polarity of one of the currents. The principle made possible the development of the asynchronous, self-starting induction motor that is…
Read More

Elihu Thomson
…to the development of successful alternating-current motors. He was also a founder of the U.S. electrical industry.
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…to the development of successful alternating-current motors. He was also a founder of the U.S. electrical industry.
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